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%I #36 Jan 03 2024 08:51:35
%S 0,1,8,68,576,4880,41344,350272,2967552,25141504,213002240,1804583936,
%T 15288680448,129527779328,1097376956416,9297126768640,78766521974784,
%U 667320682872832,5653631550881792,47898335138545664,405801207311892480,3438002999049322496
%N a(n) = 8*a(n-1) + 4*a(n-2), with a(0)=0, a(1)=1.
%H Vincenzo Librandi, <a href="/A190510/b190510.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (8,4).
%F G.f.: x/(1 - 8*x - 4*x^2). - _R. J. Mathar_, Nov 21 2011
%F a(n+1) = Sum_{k, 0<=k<=n} A099089(n,k)*4^k. - _Philippe Deléham_, Nov 21 2011
%t LinearRecurrence[{8,4}, {0,1}, 50]
%o (Magma) I:=[0, 1]; [n le 2 select I[n] else 8*Self(n-1)+4*Self(n-2): n in [1..20]]; // _Vincenzo Librandi_, Nov 23 2011
%o (PARI) x='x+O('x^30); concat([0], Vec(x/(1-8*x-4*x^2))) \\ _G. C. Greubel_, Jan 24 2018
%K nonn,easy
%O 0,3
%A _Vladimir Joseph Stephan Orlovsky_, May 24 2011
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